High-speed propulsion plant



Oct. 10, 1944. F. A. M. HEPPNER HIGH SPEED PROPULSION PLANT Filed April 2, 1942 [nvenZZr 9272 015%??? (7&2: fippiwr UZZZOrne s Batentedoct. .10, 1944 mice ' Applicaflon Alu'il 2', 42, Serial No. 437,431 i F In Great Britain March 2 1941 8 Claims.

This invention relates to a high-speed propusion plant, particularly for an aircraft, of the kind consisting of an axial-flow, contra-rotating compressor and internal-combustion turbine with a combustion chamber between them, the exhaust of the turbine giving a direct reaction drive. No mechanical energy need be taken from the plant, the turbine being of suflicient'size merelyto-operate the compressor. Preferably the airflows continuously through the plant, thecombustion chamber being an annular onearranged to interfere with the flow as little as possible.

My main object is to provide a more emcient plantofthis kind. I

A further object is to provide a single outer shell which carries the whole of the outer turbine blades and part at least of the outer compressor blades. The shell is preferably waisted along the compressor towards the combustion chamber in order to cope with the different volume of air being dealt with along the lengthof the compressor. As a matter of convenience, the shell is conveniently formed of two main parts joined to one another in a transverse plane, preferably in the vicinity of the combustion chamber.

A'further object is to arrange a single inner rotor which provides substantially the whole of the inner rotary portion of the turbine and of the combustion chamber, and part at least of the inner rotary portion of the compressor. The two rotors, that is, the shell and the inner rotor, may be Journalled through ball-bearings or other anti-friction means upon a stationary shaft.

In the accompanying sheet of diagrammatic drawings:

Figure 1 is a part-sectional elevation of one form of high-speed propulsion plant according to the invention;

Figure 2 is a fragmentary'sectional view of a modified form of compressor showing one method by which fuel can be delivered to the combustion chamber; and

Figure 3 shows, to a larger scale, three blades in cross-section of the first row of turbine blades.

In the construction shown by Figure 1, there is a stationary shaft ll supported from a stationary cowling l2 within the interior of which the plant is arranged. This consists of a single outer shell l3 built up in two parts l3a, l3b the adjacent edges of which are flanged, as shown at I4, and

bolted or otherwise secured to one another, and

from the shaft II by means of a ball-bearing l8,

(c1. Gil-35.6) v V v and at its rear end from the rear row IQ of turblue blades through a ball-bearing from the inner rotor 15." The latteris directly joumalled upon the's'haft'll. through-ball-bearings 22, 23,

flanges] 2a fast therewith.

Each row of compressor blades carried by the shell l3 has a ring-portion 26 connected by the blades 21 to a shroud 28 located at the inner periphery of the shell. Each row of compressor blades on the inner-rotor I5 .is fast with a flanged ring 29, the flanges abutting one another, and being secured on the periphery of the inner rotor as by a collar 3i. Both sets of rings (26, 29)

may be provided with labyrinths in known mane ner. In a similar way the sets of blades of the turbine are secured to the outer shell and inner rotor, respectively. Between the compressor and the turbine is the annular combustion chamber 33 which may be provided with fuel'supply and ignition means of any well known or convenient construction. p

it is preferred that the blades of the first row of the turbine (and possibly the blades of some of the next rows also) should be lipped 'on their leading edges 34 with a hard metallic alloy, as shown in Figure 3. A tapering stream-lined po'rtion 35 is in'this case fast with the inner rotor extending beyond the tapering outlet end of the cowling. Any convenient means may be made use .of for supplying fuel to the combustion chamber 33, such for example as shown in Figure 2, at 46, Y

differing speeds as to balance and therefore neutralise gyroscopicforces. Since the moment of inertia of the outer shell'is the greater, its speed is the less, and this fits in with the limits imposed by centrifugal stresses. Moreover, with speeds of rotation of the inner rotor and outer shellwithin the limits so imposed, the working circumferential speed is very high (it may easily exceed the velocity of sound in air) so that blading of small deflection coefflcient can be used. Since no torque is put into or taken out of the system (ignoring bearing friction) the exhaust gases must leave without torque and the relative speeds of the inner rotor and the outer shell can be determined by suitable blade design.

In the construction of Figure 2, the fuel is supplied along the outer shell 31 at one or more places. Thus, the fuel is delivered under pressure along the interior of the stationary shaft 40 (which in this instance is made hollow and supports, as before, the outer shell 31 and the inner rotor 4| through ball-bearings 42) and through openings 43 intov an annular groove 44 at the radially-inner edge of the annulus 45 supporting the front row of compressor blades, and thence it travels by centrifugal action along radial passages and longitudinal passages 41 to be delivered through radially-extending nozzles 48 into the combustion chamber 49.

The construction above described lends itself particularly well to mounting beneath the wing of an aircraft in the case of land planes, and since there is no propeller, air flow over the top surface of the wing is uninterrupted and also the landing gear design is simplified. Reaction propulsion is at its maximum efllciency when the vehicle speed is about half the gas discharge speed; but it also has the advantage that at starting, though the emciency also starts at zero, the actual thrust is doubled.

What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. A high-speed propulsion plant, particularly for an aircraft, comprising an axial-flow contrarotating compressor and in'temal-combustion turbine with a combustion chamber between them, the exhaust of said turbine giving a direct reaction drive, said plant having a single outer shell which carries the whole of the outer turbine blades and part at least of the outer compressor blades, and also provides the outer portion of the combustion chamber, said outer shell comprising a frusto-conical compressor portion, a frustoconical combustion chamber portion, said frustoconical portions having their apices confronting each other, and a rear frusto-conical portion having the base thereof confronting the base of said combustion chamber and forming a reaction nozzle. I

2. A high-speed propulsion plant, particularly for an aircraft, comprising an axial-flow contrarotating compressor and internal-combustion turbine with a combustion chamber between them, the. exhaust of said turbine giving a direct reactiongdrive, said plant having a singl outer shell which, carries the whole of the outer turbine blades and .part at least of the outer compressor blades; and also provides the outer portion of the combustion chamber, said outer shell being formed of two main parts joined to one another in a transverse plane, preferably in the vicinity of the combustion chamber, said outer shell comprising a frusto-conical compressor portion, a frusto-conical combustion chamber portion, said frusto-conical portions having their apices confronting each other, and a rear frusto-conical portion having the base thereof confronting the base of said combustion chamber and forming a reaction nozzle.

3. A high-speed propulsion plant, particularly for an aircraft, consisting of an axial-flow rotary a combustion chamber between them, the exhaust of said turbine giving a direct reaction drive, said plant having a single outer shell which provides substantially the whole of the outer rotary portion of the turbine and of the combustion chamber, and part at least of the outer rotary portion of the compressor, and said plant also having a single inner rotor which provides substantially the whole of the inner rotary portion of the turbine and of the combustion chamber, and part at least of the inner rotary portion of the compressor, said outer shell and inner rotor revolving in opposite directions, said outer shell comprising a frusto-conical compressor portion, a frusto-conical combustion chamber portion, said frusto-conical portions having their apices confronting each other, and a rear frusto-conical portion having the base thereof confronting the base of said combustion chamber and forming a reaction nozzle.

4. A high-speed propulsion plant, particularly for an aircraft, consisting of an axial-flow rotary compressor and internal-combustion turbine with a combustion chamber between them, the exhaust of said turbine giving a direct reaction drive, said lant having a single outer shell which provides substantially the whole of the outer rotary portion of the turbine and of the combustion chamber, and part at least of the outer rotary portion of the compressor, and said plant also having a single inner rotor which provides substantially the whole of the inner rotary portion of the turbine and of the combustion chamber, and part at least of the inner rotary portion of the compressor, said outer shell and inner rotor revolving in opposite directions and being journalled through anti-friction means upon a stationary shaft, said outer shell comprising a frustoconical compressor portion, a frusto-conical combustion chamber portion, said frusto-conical portions having their apices confronting each other,

and a rear frusto-conical portion having the base thereof confronting the base of said combustion chamber and forming a reaction nozzle.

5. A propulsion plant, according to claim 4, in which an axial streamline tail is carried by the inner rotor and in which said outer shell tapers to provide a nozzle cross-section decreasing towards the outlet end, so as to direct the gases, substantially without eddies or vacuum being formed, over the axial streamline tail carried by said inner rotor.

6. A propulsion plant, according to claim 4, in which an axial streamline tail is carried by the inner rotor to rotate therewith and in which said outer shell tapers to provide a nozzle crosssection decreasing towards the outlet end, so as to direct the gases, substantially without eddies or vacuum being formed, over the axial streamline tail carried by said inner rotor, in combination with a stationary cowling which, with the tapering outlet part of said outer shell, gives a smooth streamline profile.

7. A propulsion plant, according to claim 3, in which fuel is supplied to the combustion chamber along a passage formed in said outer shell.

8. A high speed propulsion plant comprising at. axial flow rotary compressor and internal combustion turbine with a combustion chamber between them, said plant having an outer shell which provides the rotary portion of the compressor, combustion chamber and turbine, and an inner rotor providing the inner rotary portion compressor and internal-combustion turbine with of the compressor, combustion chamber and turbine, said outer shell and inner rotor being journaled for rotation in opposite directions, said outer shell being of substantially circular cross-section and tapering from the inlet end of the compressor to the outlet end thereof and from the inlet end of the turbine to its outlet end, the portion of the shell connecting the compression and turbine forming the combustion chamber and being oppositely tapered from the inlet end of the turbine to the outlet end of the compressor the outlet end of said turbine being of smaller diameter than the inlet end thereof and constituting a reaction nozzle.

FRITZ ALBERT MAX HEPPNER. 

